@Maerad:
Honestly - the whole approach to the problem is wrong IMHO…
...Secure you Windows, work with care, get a more expensive router...
...if you are not a enthusiast user that has no problem spending hours to find problems and just want the network to function, do yourself a favor and go the easy way.
@pfBasic:
In general, pfSense won't prevent you from getting viruses. That being said it will absolutely help if implemented correctly. Best all around anti-virus is still going to be your decisions on the web and on your device.
@Maerad:
Separate networks might help a bit, but in reality, it's way too much work and investment in a private home
Eh, seriously? Separate networks take a few minutes to setup and the cost of getting a web managed switch that supports 802.11q over a "dumb" switch is pretty negligible for a home use switch.
The firewall rules are not complex at all. Just write a rule on the interface you want access from to allow access to the network that contains the device you want to access…
Buy a more expensive router that has a Guest network? One of the big draws of pfSense is the ability to run it on the old computer you have sitting in the closet from 8 years ago, or a $50 eBay/craigslist special. Out of the box, pfSense works. Any complexity is user implemented.
The $50 T420 from 2011 I have sitting on my desk with a single NIC paired with a $30 switch will easily outclass a high end SOHO router...